Distributor for engine ignition system

ABSTRACT

A distributor for an engine ignition system which comprises a rectangular electrode and a pair of U-shaped electrodes fitted on the distributor rotor. The rectangular electrode is used as a central electrode input side and the U-shaped electrodes are used as a high voltage input electrode side. Different U-shaped electrodes are alternatively used in each 90* rotation of the rotor so that the mold for the preparation of the distributor is greatly simplified and erroneous discharges to undesired ignition plugs can be prevented.

United States Patent Shibagaki et al.

DISTRIBUTOR FOR ENGINE IGNITION SYSTEM lnventors: Masao Shibagaki, Hiroshima;

Masayoshi Oonishi, Himeji, both of Japan Assignees: Toyo Kogoyo Co., Ltd., Hiroshima;

Mitsubishi Kenki Kabushiki Kaisha, Tokyo, both of Japan Filed: Aug. 22, 1973 Appl. No.: 390,517

Foreign Application Priority Data Aug. 29, 1972 Japan 47-100785 US. Cl. 123/148 DS; 123/148 E 1111. c1. F02p 5/04 Field of Search 200/19 R, 19 A, 19 DC, 200/19 DR, 20, 21, 23, 24, 26, 28, 8 R, 153 5; 315/209 R, 204 M, 210, 211, 212, 226; 123/146.5 A, 148 R, 148 DS,148 A, 148 c, 148 E; 310/231-237 References Cited UNITED STATES PATENTS 4/1915 Butts 200/8 R UX June 24, 1975 1,604,630 10/1926 Ewen 200/8 R 2,555,488 6/1951 l-letzler et a1 200/19 DR X 2,954,506 9/1960 Harkness 315/226 X 3,028,563 4/1962 Morrison 200/153 S 3,435,161 3/1969 Webster 200/190 C 3,504,141 3/1970 Webster 200/19 DC 3,794,008 2/1974 Mathews 123/148 DS Primary Examiner--James R. Scott Attorney, Agent, or FirmOblon, Fisher, Spivak, McClelland & Maier [5 7] ABSTRACT A distributor for an engine ignition system which comprises a rectangular electrode and a pair of U-shaped electrodes fitted on the distributor rotor. The rectangular electrode is used as a central electrode input side and the U-shaped electrodes are used as a high voltage input electrode side. Different .U-shaped electrodes are alternatively used in each 90 rotation of the rotor so that the mold for the preparation of the distributor is greatly simplified and erroneous discharges to undesired ignition plugs can be prevented.

3 Claims, 6 Drawing Figures DISTRIBUTOR FOR ENGINE IGNITION SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a distributor for an engine ignition system.

2. Description of the Prior Art In a conventional distribution part used for an ignition distributor for two-cycle, two-cylinder engines having two spark plugs in one cylinder, a high voltage input is supplied from a central electrode of a cap through a carbon electrode to a rotatable, elongated,

' substantially rectangular electrode extending radially about the same distance from the center of the distribution rotor. When the rotatable electrode faces a peripheral electrode of the cap, an interrupter is turned off whereby the high voltage generated in the ignition coil is distributed from the central electrode through the distribution rotor electrode to the ignition spark plugs for the engine. The other high voltage input is supplied from a high voltage input electrode displaced from the central electrode by a certain distance, and passed through a carbon ring electrode of the distribution rotor. Projected electrodes are formed on two parts of the ring electrode at 180 angles. When a projected electrode faces a peripheral electrode, the interrupter is turned off so that the high voltage generated in the ignition coil is supplied from the high voltage input electrode through the ring electrode to the ignition spark plug for the engine.

The double high voltage distribution systems form independent ignition systems. However, in such conventional apparatus, the distributor rotor forms a ring electrode, so that a mold for preparing the body is complicated. Further, abrasion of the carbon in contact with the ring electrode occurs more rapidly than that of the carbon fitted on the central electrode due to the faster peripheral velocity. The abrasion creates powdery carbon which impairs the sparking characteristics of the system. Moreover, when the high voltage is applied to the high voltage input electrode, the high voltage is applied to the ring electrode, so that it is difficult to increase the other ignition system of central electrode, the 180 electrode and the space from the peripheral cap electrode; however, a high mix gas pressure is applied to the appropriate ignition plug so that the spark discharging voltage is high. Accordingly, the spark discharge is very difficult to achieve so that an erroneous discharge to an undesired ignition plug may occur. In order to prevent such an erroneous discharge, the peripheral cap electrode, the ring electrode and the space between the ring electrode and the central electrode are increased, or the space between the rotary electrode of the distributor rotor and the ring electrode is increased in the axial direction. As a result, the total size of the distributor increases and the axial length is long. This disadvantageously requires a large space to fit the distributor.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a distributor for an engine ignition system which prevents erroneous discharges and has a simple and economical structure including a narrow gap between the electrodes.

The foregoing and other objects are attained in accordance with one aspect of the present invention through the provision of a distributor for an engine ignition system which comprises an elongated, substantially rectangular electrode and a pair of U-shaped electrodes fitted on the distributor rotor wherein the rectangular electrode is used in the central electrode side and the U-shaped electrodes are used in the high voltage input electrode side and a different U-shaped electrode is alternatively used in each rotation of the rotor.

BRIEF DESCRIPTION OF THE DRAWINGS Various objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description of the present invention when considered in connection with the accompanying drawings, in which:

FIG. 1 is a plan view of an embodiment of a distributor cap according to the present invention; and

FIG. 2 is a schematic view of a preferred embodiment distribution system according to the present invention;

FIGS. 3A, 3B, 3C and 3D illustrate the firing sequence of the distribution system of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIGS. 1 and 2 thereof, a preferred embodiment according to this invention is illustrated as comprising a distributor cap 1; a central electrode 2; a first peripheral electrode 3; a second peripheral electrode 4; a high voltage input electrode 5; a third peripheral electrode 6; a fourth peripheral electrode 7; an elongated, substantially rectangular electrode 8 of a distribution rotor 1 l; a U-shaped first electrode 9 of distribution rotor l l; a U-shaped second electrode 10 of distribution rotor 11; a battery 12; a first ignition coil 13; a first interrupter 14; a condenser 15 for preventing a spark during the contact of the first interrupter 14; a second ignition coil 16; a second interrupter 1.7; a condenser 18 for preventing a spark during the contact of the second interrupter 17; a first ignition plug 19 fitted to the first cylinder 23; a second ignition plug 20 fitted to the second cylinder 24; a third ignition plug 21 fitted to the first cylinder 23; and a fourth ignition plug 22 fitted to the second cylinder 24. The reference numerals 3a, 4a, 5a, 6a and 7a designate peripheral cap electrodes and high voltage input electrodes which alternately face the rectangular electrode 8 and the first and second U- shaped electrodes 9 and 10, in a manner which will be described more fully hereinafter.

The first ignition system is formed by the first ignition coil 13, the first interrupter 14, the condenser 15, the central electrode 2, the rectangular electrode 8, the first peripheral electrodes 3 and 3a, the second peripheral electrodes 4 and 4a, the first ignition plug 19, and the second ignition plug 20.

The second ignition system is formed by the second ignition coil 16, the second interrupter 17, the condenser 18, the high voltage input electrodes 5 and 5a, the first U-shaped electrode 9, the third peripheral electrodes 6 and 6a, the third ignition plug 21, the second U-shaped electrode 10, the fourth peripheral electrodes 7 and 7a, and the fourth ignition plug 22.

In operation, when the engine is cranked and the first interrupter 14 is changed from a turn-on condition to a turn-off condition, a high voltage (such as 30 KV) is induced in the secondary winding of the first ignition coil 13. The high voltage is applied to the central electrode 2 and is supplied through a carbon electrode to the first electrode 3 facing the rectangular electrode 8, so that the first ignition plug 19 of the first cylinder 23 creates a spark discharge to contribute to the rotation of the engine.

When the second interrupter 17 is converted from a turn-on to a turn-off condition (with a short delay from the first interrupter 14), a high voltage is induced in the second ignition coil 16 and is supplied through the high voltage input electrodes 5 and 5a, through the second U-shaped electrode to the third electrodes 6 and 6a, so that a spark-discharge is created in the third ignition plug 21 of the first cylinder 23. That is, in the first cylinder 23, the third ignition plug 21 is spark-discharged with a phase delay of a certain angle after the ignition of the first ignition plug 19.

Thereafter, the engine is recycled and the first inter rupter 14 and the second interrupter 17 are turned on to accumulate energy in the primary of the ignition coils 13 and 16 by reversing the first interrupter 14 and the second interrupter 17, and then the first interrupter 14 is turned off. At this point, the distribution rotor 11 is advanced 90 clockwise within cap 1 from the position shown in FIG. 2. The rectangular electrode 8 then faces the second electrodes 4 and 4a, and the first U- shaped electrode 9 connects the high voltage input electrodes 5 and 5a to the fourth peripheral electrodes 7 and'7a.

In according with the operation of the first interrupter 14, a high voltage is applied from the first ignition coil 13 to the central electrode 2, and is supplied through the rectangular electrode 8 to the second electrode 4 so as to create a spark discharge at the second ignition plug of the second cylinder 24. When the second interrupter 17 is turned off following the first interrupter 14, a high voltage is induced in the second ignition coil 16 and is applied to the high voltage input electrode 5 and to the fourth electrode 7 by the first U- shaped electrode 9, so as to create a spark discharge in .the fourth ignition plug 22 of the second cylinder 24,

- tributes the voltage to the third ignition plug 21 and the fourth ignition plug 22 also for each 90 rotation of the rotary shaft of the distributor. The ignition systems thus form independent ignition systems.

In accordance with this invention, a rectangular electrode and a pair of U-shaped electrodes are fitted on the distributor rotor 11. The rectangular electrode is used as a central electrode and the U-shaped electrodes are used as high voltage input electrodes set in the periphery of the cap, and a different U-shaped electrode is alternatively used in each 90 rotation, so that the mold for the preparation of the distributor is greatly simplified.

Thus, the high voltage input electrodes whose peripheral velocity is high are of the gap type, so that the trouble in the prior art caused by powdery carbon is virtually eliminated. The pair of U-shaped electrodes are arranged in positions of 180 phase. so that an erroneous discharge to an undesired ignition plug can be prevented, and the distributor can be made compact to provide quite advantageous results.

FIGS. 3A, 3B, 3C and 3D illustrate the firing sequence of the distribution system of FIG. 2. The firing sequence is 1324 and is accomplished in the following manner.

In FIG. 3A, first ignition coil 13 is connected to first ignition plug 19 by electrode 8 through the dotted lines shown in the FIGURE. Second ignition coil 16 is connected to third ignition plug 21 by electrode 10. First ignition coil 13 is fired first igniting first ignition plug 19. Second ignition coil 16 is then fired igniting third ignition plug 21. Neither second ignition plug 20 nor fourth ignition plug 22 is ignited during this position of the distribution rotor.

The distribution rotor is then rotated clockwise so that the position shown in FIG. 3B is realized. First ignition coil 13 is again fired first and ignites second ignition plug 20 through electrode 8. Second ignition coil 16 is fired thereafter to ignite fourth ignition plug 22 through electrode 9. Note that during this position of the distribution rotor there is no connection between ignition coils 13 and 16 and first and third ignition plugs 19 and 21.

The distribution rotor is then rotated 90 further in a clockwise direction until the position shown in FIG. 3C is assumed. Note that the position shown in FIG. 3C is similar to that shown in FIG. 3A with the exception that electrodes 9 and 10 have reversed positions. It is believed clear from FIG. 3C that the firing sequences in FIGS. 3A and 3C are identical.

The distribution rotor is then rotated 90 further in a clockwise direction until the position shown in 3D is assumed. It is believed apparent that the position in FIG. 3D is similar to the position shown in FIG. 3B with the exception that electrodes 9 and 10 have reversed positions. It is also believed clear that the firing sequences of FIGS. 38 and 3D are identical.

Thus, as shown in FIGS. 3A-3D, the firing sequence is 13-241-3-24 for every 360 rotation of the distribution rotor.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An ignition system comprising a first ignition plug,

a second ignition plug,

a third ignition plug,

a fourth ignition plug,

a first ignition coil,

a second ignition coil,

a first peripheral electrode,

a second peripheral electrode,

a third peripheral electrode,

a fourth peripheral electrode,

a fifth peripheral electrode,

said first, second, third, fourth and fifth peripheral electrodes being mounted to a distributor cap so that each of said peripheral electrodes is equidistant from the center of said distributor cap and so that said peripheral electrodes are disposed in a clockwise direction with the second electrode 90 from the first electrode, the fourth electrode 45 from the second electrode, the fifth electrode 90 from the fourth electrode and the third electrode 90 from the fifth electrode,

a distribution rotor having the same center as said distribution cap,

a first rotor electrode being mounted to said distribution rotor so that its ends span a first are on said distribution rotor and on said distribution cap of 90,

a second rotor electrode being mounted to said distribution rotor so that its ends span a second arc on said distribution rotor and on said distribution cap of 90 and so that said first arc and second are are diametrically opposed,

a third rotor electrode being mounted to said distribution rotor so that its ends span a third are on said distribution rotor and on said distribution cap of 180 and so that the ends of said third electrode lie midway between adjacent ends of said first and second rotor electrodes,

means connecting said first ignition coil to said third rotor electrode,

means connecting said second ignition coil to said fifth peripheral electrode,

means connecting said first ignition plug to said first peripheral electrode,

means connecting said second ignition plug to said second peripheral electrode,

means connecting said third ignition plug to said third peripheral electrode,

means connecting said fourth ignition plug to said fourth peripheral electrode.

2. An ignition system in accordance with claim 1 wherein said second rotor electrode connects said fifth peripheral electrode to said third peripheral electrode and wherein said third rotor electrode connects said first ignition coil to said first peripheral electrode at a first position of said distribution rotor and wherein said first rotor electrode connects said fourth peripheral electrode to said fifth peripheral electrode and said third rotor electrode connects said first ignition coil to said second peripheral electrode at a second position of said distribution rotor.

3. An ignition system in accordance with claim 2 wherein said first ignition plug and said third ignition plug are mounted in a first cylinder and said second ignition plug and said fourth ignition plug are mounted in a second cylinder.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 1 3,890,947 DATED June 24, 1975 |NVENTOR(S) Masao Shibagaki and Masayoshi Oonishi It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Change Assignee from "Toyo Kogoyo (30., Ltd. & Mitsubishi Kenki Kabushiki Kaisha" to --Toy0 Kogyo Co. Ltd. & Mitsubishi Denki Kabushiki Kaisha--.

Signed and Scaled this third Day Of February 1976 [SEAL] AIItZSI.

RUTH c. MASON c. MARSHALL DANN Arresting Officer Commissioner ofParents and Trademarks 

1. An ignition system comprising a first ignition plug, a second ignition plug, a third ignition plug, a fourth ignition plug, a first ignition coil, a second ignition coil, a first peripheral electrode, a second peripheral electrode, a third peripheral electrode, a fourth peripheral electrode, a fifth peripheral electrode, said first, second, third, fourth and fifth peripheral electrodes being mounted to a distributor cap so that each of said peripheral electrodes is equidistant from the center of said distributor cap and so that said peripheral electrodes are disposed in a clockwise direction with the second electrode 90* from the first electrode, the fourth electrode 45* from the second electrode, the fifth electrode 90* from the fourth electrode and the third electrode 90* from the fifth electrode, a distribution rotor having the same center as said distribution cap, a first rotor electrode being mounted to said distribution rotor so that its ends span a first arc on said distribution rotor and on said distribution cap of 90*, a second rotor electrode being mounted to said distribution rotor so that its ends span a second arc on said distribution rotor and on said distribution cap of 90* and so that said first arc and second arc are diametrically opposed, a third rotor electrode being mounted to said distribution rotor so that its ends span a third arc on said distribution rotor and on said Distribution cap of 180* and so that the ends of said third electrode lie midway between adjacent ends of said first and second rotor electrodes, means connecting said first ignition coil to said third rotor electrode, means connecting said second ignition coil to said fifth peripheral electrode, means connecting said first ignition plug to said first peripheral electrode, means connecting said second ignition plug to said second peripheral electrode, means connecting said third ignition plug to said third peripheral electrode, means connecting said fourth ignition plug to said fourth peripheral electrode.
 2. An ignition system in accordance with claim 1 wherein said second rotor electrode connects said fifth peripheral electrode to said third peripheral electrode and wherein said third rotor electrode connects said first ignition coil to said first peripheral electrode at a first position of said distribution rotor and wherein said first rotor electrode connects said fourth peripheral electrode to said fifth peripheral electrode and said third rotor electrode connects said first ignition coil to said second peripheral electrode at a second position of said distribution rotor.
 3. An ignition system in accordance with claim 2 wherein said first ignition plug and said third ignition plug are mounted in a first cylinder and said second ignition plug and said fourth ignition plug are mounted in a second cylinder. 